Ability to optionally use forked gemini-cli

[oprudkyi]

TL;DR

add inputs.gemini_cli_package defaulted to @google/gemini-cli

Detailed design

similar to gemini_cli_version, vars.GEMINI_CLI_VERSION

Additional information

I will provide PR

[gemini-cli]

🤖 Hi @oprudkyi, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.